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231.
数字化博物馆是博物馆现代化的一个重要标志。国外博物馆从20世纪90年代就开始进行数字化建设,国内的博物馆数字化建设起步较晚,同国外的先进技术相比还有一定的差距,但发展较快。目前,国内外已有的昆虫数字化博物馆各具特色,有以展示昆虫图片为主的,有以介绍昆虫知识为主的,也有以营利为目的的,但仍有不少需要改进的地方。为了满足中小学生的求知欲和探索欲,适应他们喜欢自己动手操作和活泼好动的性格,昆虫数字化博物馆网站建设在技术上应采用J2EE三层体系结构,采用动态网站内容管理与发布系统构建的后台管理系统,将昆虫数字化博物馆分成后台管理和前台展示与交互两部分,从而实现网站内容与表现形式的分离,加快网页更新的速度。在数据库建设上,应采用功能强大的数据库软件,以满足大量图片、声音、动画、视频等多种类型的数据库的有效存储和高效的检索功能。在网站的内容上应有实体展厅的数字化、昆虫学术交流与知识集锦、中小学生互动教育等板块。在网站的后期维护上应做到由全社会的昆虫爱好者共同维护和管理。  相似文献   
232.
Alveolar epithelial cell (AEC) injury and repair during hyperoxia exposure and recovery have been investigated for decades, but the molecular mechanisms of these processes are not clear. To identify potentially important genes involved in lung injury and repair, we studied the gene expression profiles of isolated AEC II from control, 48-h hyperoxia-exposed (>95% O(2)), and 1-7 day recovering rats using a DNA microarray containing 10,000 genes. Fifty genes showed significant differential expression between two or more time points (P<0.05, fold change >2). These genes can be classified into 8 unique gene expression patterns. Real-time PCR verified 14 selected genes in three patterns related to hyperoxia exposure and early recovery. The change in the protein level for two of the selected genes, bmp-4 and retnla, paralleled that of the mRNA level. Many of these genes were found to be involved in cell proliferation and differentiation. In an in vitro AEC trans-differentiation culture model using AEC II isolated from control and 48-h hyperoxia-exposed rats, the expressions of the cell proliferation and differentiation genes identified above were consistent with their predicted roles in the trans-differentiation of AEC. These data indicate that a coordinated mechanism may control AEC differentiation during in vivo hyperoxia exposure and recovery as well as during in vitro AEC culture.  相似文献   
233.
【目的】探索低浓度红霉素对猪链球菌蛋白表达、交叉耐药性与荚膜多糖的影响,为进一步研究饲料中低浓度抗生素促生长剂对环境中微生物的影响奠定基础。【方法】猪链球菌接触低浓度红霉素后,利用蛋白质组学iTRAQ技术,筛选关键差异表达蛋白。同时测定猪链球菌的交叉耐药性和荚膜多糖含量。【结果】共鉴定到差异表达蛋白181个,占总鉴定蛋白的12%,猪链球菌通过改变自身蛋白质组的表达量,以适应红霉素的选择性压力。多数差异表达蛋白参与催化和代谢过程,属于膜蛋白,其中13个ATP结合盒转运蛋白、3个核糖体蛋白、DNA回旋酶上调表达,8个荚膜多糖蛋白、DNA聚合酶Ⅳ下调表达。接触低浓度红霉素后,猪链球菌对多种抗生素出现交叉耐药性,消除红霉素后,药物敏感性恢复。接触低浓度红霉素后,荚膜多糖含量也未发生大幅度变化。【结论】猪链球菌为适应低浓度红霉素的选择性压力,大量表达多重耐药的主动外排泵,增加核糖体蛋白的表达量,降低荚膜多糖蛋白的表达量。  相似文献   
234.
【目的】从嗜盐古菌中筛选可产生生物絮凝剂的菌株,对发酵液、上清液、菌悬液、胞外聚合物的絮凝作用进行检测,筛选能够适应高盐废水处理,且具有广谱盐度及pH作用范围的微生物絮凝剂。【方法】以新疆乌勇布拉克干盐湖沉积物为研究对象,利用纯培养方法对嗜盐古菌进行分离,对絮凝菌株进行初筛及16S rRNA基因测序,构建系统进化树,初步判断菌株分类地位;复筛检测不同生物材料的絮凝效果;选择絮凝效果较好的生物材料,检测其盐度、pH的絮凝效果稳定性。【结果】采用纯培养方法共分离到28株嗜盐古菌,絮凝初筛共筛选出16株嗜盐古菌,分布于碱线菌属(Natrinema)、盐缓长菌属(Halopiger)和盐土生菌属(Haloterrigena)。菌株发酵液、上清液、菌悬液、胞外聚合物具有不同程度的絮凝效果。菌株A279-1、A133、RP33、NGA0064、RM-152、A389的发酵液、上清液的絮凝效果较好,其中菌株A389的发酵液絮凝率为61.06%,上清液为67.92%。所有菌株菌悬液的絮凝率达到80%以上。菌株所产胞外聚合物表现出较好的絮凝效果,菌株RM-152所产胞外聚合物的絮凝率最高,达89.86%,其次是A389 (81.53%)。菌株A389所产胞外聚合物的产量最大,达12.53 g/L,具有广泛的盐度和pH适应性。【结论】乌勇布拉克干盐湖沉积物中蕴含丰富的可产生微生物絮凝剂的嗜盐古菌资源。嗜盐古菌菌株发酵液、上清液、菌悬液及胞外聚合物均具有良好的絮凝作用,尤其是胞外聚合物表现出较好的絮凝效果,具有广谱的盐度和pH耐受性。嗜盐古菌所产生物絮凝剂的发现对于后续高盐废水功能材料开发具有重要应用价值。  相似文献   
235.
Drought stress negatively impacts growth and physiological processes in plants. The foliar application of glycine betaine (GB) is an effective and low-cost approach to improve the drought tolerance of trees. This study examined the effect of exogenously applied GB on the cell membrane permeability, osmotic adjustment, and antioxidant enzyme activities of Phoebe hunanensis Hand.-Mazz under drought stress. Two levels (0 and 800 mL) of water irrigation were tested under different applied GB concentrations (0, 50, 100, and 200 mM). Drought stress decreased the relative water content by 58.5% while increased the electric conductivity, malondialdehyde, proline, soluble proteins, soluble sugars, and antioxidant enzyme activities (superoxide dismutase, catalase, peroxidase) by up to 62.9%, 42.4%, 87.0%, 19.1%, 60.5%, 68.3%, 71.7%, and 83.8%, respectively, on the 25th day. The foliar application of GB, especially at 100 mM, increased the relative water content of P. hunanensis leaves under drought stress. The concentration of GB from 50 to 100 mM effectively alleviated the improvement of cell membrane permeability and inhibited the accumulation of membrane lipid peroxidation products. Under drought stress, the concentrations of proline, soluble proteins, and soluble sugars in the leaves of P. hunanensis increased as the applied GB concentration was increased and the water stress time was prolonged. Exogenously applied GB decreased oxidative stress and improved antioxidant enzyme activities as compared with treatments without GB application. Furthermore, the physiological and biochemical indexes of P. hunanensis showed a certain dose effect on exogenous GB concentration. These results suggest that GB helps maintain the drought tolerance of P. hunanensis.  相似文献   
236.
A cavitation event in a vessel replaces water with a mixture of water vapor and air. A quantitative theory is presented to argue that the tempo of filling of vessels with air has two phases: a fast process that extracts air from stem tissue adjacent to the cavitated vessels (less than 10 s) and a slow phase that extracts air from the atmosphere outside the stem (more than 10 h). A model was designed to estimate how water tension (T) near recently cavitated vessels causes bubbles in embolized vessels to expand or contract as T increases or decreases, respectively. The model also predicts that the hydraulic conductivity of a stem will increase as bubbles collapse. The pressure of air bubbles trapped in vessels of a stem can be predicted from the model based on fitting curves of hydraulic conductivity versus T. The model was validated using data from six stem segments each of Acer mono and the clonal hybrid Populus 84K (Populus alba × Populus glandulosa). The model was fitted to results with root mean square error less than 3%. The model provided new insight into the study of embolism formation in stem tissue and helped quantify the bubble pressure immediately after the fast process referred to above.Vulnerability curves (VCs) have been viewed as a good measure of the drought resistance of woody stems (Cochard et al., 2013). Increasing drought increases the xylem tension (T) and eventually induces cavitation of the water in conduits when the T exceeds a certain threshold (Sperry and Tyree, 1988; Sperry et al., 1996). A cavitated vessel first fills with water vapor and eventually fills with air at atmospheric pressure because of Henry’s law, which describes gas equilibrium at the water/air interface. The time required for the progress mainly depends on the penetration rate of air into the recently cavitated vessel lumen via diffusion through the liquid phase.Previous studies were made about how fast bubbles disappear in embolized stems because of the solubility of air in water when water pressure exceeds atmospheric pressure, and the process takes 10 to 100 h depending on conditions (Tyree and Yang, 1992; Yang and Tyree, 1992). The tempo of bubble disappearance was measured by following the rise in stem hydraulic conductivity (kh) versus time. The theory of Yang and Tyree (1992) relied on the same principles used in this article (Henry’s law, Fick’s law, and the ideal gas law), but modeling and experiments were done at pressures between 1 and 3 times atmospheric pressure rather than subatmospheric pressure (negative pressure). However, much less is known about the tempo of bubble formation in recently cavitated vessels (Brodersen et al., 2013). If the progress of embolus formation takes several minutes, then no changes in conductivity could be observed with available techniques, but if it takes hours, then the tempo of bubbles can be studied by rapidly inducing cavitation with increasing T and after cavitation induction measuring the influence of T on stem kh as T is reduced gradually to zero. If air bubbles are at a pressure (bubble pressure [Pb*]) lower than a threshold near atmospheric pressure, bubbles ought to collapse when T decreases according to the ideal gas law and Henry’s law (see theory below). The consequence of bubble collapse will be partial filling of vessels with water and the rest with air bubbles. The partial filling of water in a recently cavitated vessel ought to increase the lumen conductivity from zero and connect the embolized vessel to adjacent conductive vessels and, hence, ought to increase the conductivity of the stem by an additional flow pathway (Wheeler et al., 2005; Hacke et al., 2006). The vascular system of stems is a complicated network with vessels of different lengths, diameters, and orientation (Evert, 2006), and the complex vessel network makes the additional pathway possible. Therefore, bubble collapse could be detected through the impact of T on the kh of the stems in a way that is very similar to the methods used by Yang and Tyree (1992) but requires a more sophisticated centrifuge technique to induce embolism.Many studies have assumed that the bubble pressure in newly cavitated vessels ought to be near atmospheric pressure, and no corrections for bubble pressure have been taken in measuring percentage loss of conductivity (PLC) when T is lower than a critical threshold (Li et al., 2008; Wang et al., 2014a). As a result of bubble collapse, the measured kh under a mild T should be higher than that under high T (greater than 0.5 MPa). And the lower the initial bubble pressure, the more bubbles collapse with decreasing T.The aim of this study is to construct a model that estimates average bubble pressure in partly embolized stems from the functional dependence of kh on T, and with this model, we can further our understanding of the tempo of bubble formation in stems. Here, we will argue that the tempo of bubble formation is in two phases: an initial rapid phase (seconds to minutes to complete) followed by a much slower phase (many hours to complete). Since there is no method for measuring the rapid phase, the rapid phase will be described theoretically below. Next, a theory will be developed that allows the estimation of the pressure of air in recently formed bubbles in vessels during the slow phase. An experimental validation of the model will follow that will yield values of bubble pressure within the first 1 to 2 h following the fast phase of embolism formation in vessels.  相似文献   
237.
238.
Auxin and brassinosteroid (BR) are important phytohormones for controlling lamina inclination implicated in plant architecture and grain yield. But the molecular mechanism of auxin and BR crosstalk for regulating lamina inclination remains unknown. Auxin response factors (ARFs) control various aspects of plant growth and development. We here report that OsARF19‐overexpression rice lines show an enlarged lamina inclination due to increase of its adaxial cell division. OsARF19 is expressed in various organs including lamina joint and strongly induced by auxin and BR. Chromatin immunoprecipitation (ChIP) and yeast one‐hybrid assays demonstrate that OsARF19 binds to the promoter of OsGH3‐5 and brassinosteroid insensitive 1 (OsBRI1) directing their expression. OsGH3‐5‐overexpression lines show a similar phenotype as OsARF19‐O1. Free auxin contents in the lamina joint of OsGH3‐5‐O1 or OsARF19‐O1 are reduced. OsGH3‐5 is localized at the endoplasmic retieulum (ER) matching reduction of the free auxin contents in OsGH3‐5‐O1. osarf19‐TDNA and osgh3‐5‐Tos17 mutants without erected leaves show a function redundancy with other members of their gene family. OsARF19‐overexpression lines are sensitive to exogenous BR treatment and alter the expressions of genes related to BR signalling. These findings provide novel insights into auxin and BR signalling, and might have significant implications for improving plant architecture of monocot crops.  相似文献   
239.
为探究不同社会地位的亚成体克氏原螯虾(Procambarus clarkii)对利益的分配,以及对社会环境改变(体型较大的入侵同类)各自做出的行为反应,本文统计已确立等级序列的成对同性别螯虾对隐蔽所的占有情况,并视频拍摄同性别螯虾入侵时,入侵者及不同地位的原居者的格斗行为,分析格斗次数、格斗时间、首次攻击及被首次攻击对象多个参数。在隐蔽所占有实验中,71%为优势者占有隐蔽所,7%为从属者占有,共同占有或没有占有的各11%。在入侵-反入侵实验中,雄性入侵者对2只原居虾之间的攻击选择无显著差异,雌性入侵者首次攻击显著选择与原优势者格斗;雄性原居者中优势者对入侵者和原从属者的攻击无显著差异,雌性优势者则显著选择与入侵者格斗;雄性原居者中从属者显著选择与入侵者格斗,雌性从属者对入侵者和原优势者的攻击无显著差异。上述结果表明,优势者优先占有资源;雌雄螯虾在入侵和面临入侵时有各自不同的策略;不同地位的螯虾在反入侵时行为反应也各有不同。  相似文献   
240.
回声定位声波地理差异及其形成原因是蝙蝠生态学研究领域一个基本而关键的问题,对于探索物种生存机制、物种形成及其保护具有重要科学意义。本研究从较大地理尺度上(9个地理种群)研究了菲菊头蝠(Rhinolophus pusillus)回声定位声波结构的地理差异,并进一步探讨了影响回声定位声波地理种群差异的因素。结果表明,菲菊头蝠雌性的体型较雄性略大,其主频较高。不同地理种群之间回声定位声波差异明显,包括脉冲持续时间、脉冲间隔、主频以及带宽在不同的地理种群之间均表现出一定程度的差异。进一步分析发现,不同地理种群之间的雌性菲菊头蝠前臂长和体重均与主频呈较弱的负相关,降雨量与雌性的主频呈较强的正相关;而不同地理种群之间的雄性前臂长、体重和降雨量与回声定位声波参数均无相关性;此外,地理距离、温度、湿度均与雌雄回声定位声波参数无相关性。本研究结果表明,菲菊头蝠不同地理种群间的回声定位声波出现明显差异,其中,体型和降雨量为主要影响因子,说明蝙蝠回声定位叫声的进化主要受到了当地生境的影响,表现出动物对不同生境的适应性进化。  相似文献   
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